ACPI / property: Extend device_get_next_child_node() to data-only nodes

Make device_get_next_child_node() work with ACPI data-only subnodes
introduced previously.

Namely, replace acpi_get_next_child() with acpi_get_next_subnode()
that can handle (and return) child device objects as well as child
data-only subnodes of the given device and modify the ACPI part
of the GPIO subsystem to handle data-only subnodes returned by it.

To that end, introduce acpi_node_get_gpiod() taking a struct
fwnode_handle pointer as the first argument.  That argument may
point to an ACPI device object as well as to a data-only subnode
and the function should do the right thing (ie. look for the matching
GPIO descriptor correctly) in either case.

Next, modify fwnode_get_named_gpiod() to use acpi_node_get_gpiod()
instead of acpi_get_gpiod_by_index() which automatically causes
devm_get_gpiod_from_child() to work with ACPI data-only subnodes
that may be returned by device_get_next_child_node() which in turn
is required by the users of that function (the gpio_keys_polled
and gpio-leds drivers).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 6be94ba..865d948 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -758,9 +758,9 @@
 #ifdef CONFIG_ACPI
 int acpi_dev_get_property(struct acpi_device *adev, const char *name,
 			  acpi_object_type type, const union acpi_object **obj);
-int acpi_dev_get_property_reference(struct acpi_device *adev,
-				    const char *name, size_t index,
-				    struct acpi_reference_args *args);
+int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
+				     const char *name, size_t index,
+				     struct acpi_reference_args *args);
 
 int acpi_node_prop_get(struct fwnode_handle *fwnode, const char *propname,
 		       void **valptr);
@@ -771,8 +771,8 @@
 int acpi_dev_prop_read(struct acpi_device *adev, const char *propname,
 		       enum dev_prop_type proptype, void *val, size_t nval);
 
-struct acpi_device *acpi_get_next_child(struct device *dev,
-					struct acpi_device *child);
+struct fwnode_handle *acpi_get_next_subnode(struct device *dev,
+					    struct fwnode_handle *subnode);
 #else
 static inline int acpi_dev_get_property(struct acpi_device *adev,
 					const char *name, acpi_object_type type,
@@ -781,7 +781,7 @@
 	return -ENXIO;
 }
 
-static inline int acpi_dev_get_property_reference(struct acpi_device *adev,
+static inline int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
 				const char *name, const char *cells_name,
 				size_t index, struct acpi_reference_args *args)
 {
@@ -826,12 +826,11 @@
 	return -ENXIO;
 }
 
-static inline struct acpi_device *acpi_get_next_child(struct device *dev,
-						      struct acpi_device *child)
+static inline struct fwnode_handle *acpi_get_next_subnode(struct device *dev,
+						struct fwnode_handle *subnode)
 {
 	return NULL;
 }
-
 #endif
 
 #endif	/*_LINUX_ACPI_H*/